﻿using System;
using Windows.UI.Xaml.Data;

namespace MugenMvvmToolkit.Converters
{
    /// <summary>
    ///     This converter reverses a Boolean value (True == False, False == True).
    /// </summary>
    public sealed class InverseBooleanConverter : IValueConverter
    {
        #region Implementation of IValueConverter

        /// <summary>
        ///     Converts a value.
        /// </summary>
        /// <returns>
        ///     A converted value. If the method returns null, the valid null value is used.
        /// </returns>
        /// <param name="value">
        ///     The value produced by the binding source.
        /// </param>
        /// <param name="targetType">
        ///     The type of the binding target property.
        /// </param>
        /// <param name="parameter">
        ///     The converter parameter to use.
        /// </param>
        /// <param name="language">
        ///     The culture to use in the converter.
        /// </param>
        public object Convert(object value, Type targetType, object parameter, string language)
        {
            if (targetType != typeof (bool))
                throw new InvalidOperationException("The target must be a boolean");
            return !(bool) value;
        }

        /// <summary>
        ///     Converts a value.
        /// </summary>
        /// <returns>
        ///     A converted value. If the method returns null, the valid null value is used.
        /// </returns>
        /// <param name="value">
        ///     The value that is produced by the binding target.
        /// </param>
        /// <param name="targetType">
        ///     The type to convert to.
        /// </param>
        /// <param name="parameter">
        ///     The converter parameter to use.
        /// </param>
        /// <param name="language">
        ///     The culture to use in the converter.
        /// </param>
        public object ConvertBack(object value, Type targetType, object parameter, string language)
        {
            if (targetType != typeof (bool))
                throw new InvalidOperationException("The target must be a boolean");
            return !(bool) value;
        }

        #endregion
    }
}